5,912 research outputs found

    Cars, capitalism and ecological crises: understanding systemic barriers to a sustainability transition in the German car industry

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    In the face of climate and ecological crises, it is vital that car use be reduced, while simultaneously shifting towards different powertrains and reducing the size, weight and energy demand of vehicles. This poses a challenge to the global car industry, as its business model historically centres on selling more and larger cars. In this context, the purpose of this paper is to examine the social-ecological limits of industrial restructuring in Germany. A narrative literature review through the lens of Marxian political economy sheds light on intertwined system-immanent barriers to achieving social and ecological sustainability at the sectoral level. Consequently, powertrain electrification is structured by technological dynamism, which fuels appropriation in the quest for metals and rare earths, with significant social and ecological disadvantages. This generates an impasse for the industry’s transition strategies. Understanding how capitalist tendencies generate interlaced and mutually re-enforcing barriers to achieving social-ecological sustainability is key to understanding why industrial transitions are insufficient from a social-ecological perspective

    On the appearance of hyperons in neutron stars

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    By employing a recently constructed hyperon-nucleon potential the equation of state of \beta-equilibrated and charge neutral nucleonic matter is calculated. The hyperon-nucleon potential is a low-momentum potential which is obtained within a renormalization group framework. Based on the Hartree-Fock approximation at zero temperature the densities at which hyperons appear in neutron stars are estimated. For several different bare hyperon-nucleon potentials and a wide range of nuclear matter parameters it is found that hyperons in neutron stars are always present. These findings have profound consequences for the mass and radius of neutron stars.Comment: 12 pages, 12 figures, RevTeX4; summary and conclusions are strengthened, to appear in PR

    XMM-Newton discovery of a sharp spectral feature at ~7 keV in the Narrow-Line Seyfert 1 galaxy 1H 0707-495

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    We report the first detection of a sharp spectral feature in a Narrow-Line Seyfert 1 galaxy. Using XMM-Newton we have observed 1H0707-495 and find a drop in flux by a factor of more than 2 at a rest-frame energy of ~7 keV without any detectable narrow Fe K alpha line emission. The energy of this feature suggests a connection with the neutral iron K photoelectric edge, but the lack of any obvious absorption in the spectrum at lower energies makes the interpretation challenging. We explore two alternative explanations for this unusual spectral feature: (i) partial covering absorption by clouds of neutral material and (ii) ionised disc reflection with lines and edges from different ionisation stages of iron blurred together by relativistic effects. We note that both models require an iron overabundance to explain the depth of the feature. The X-ray light curve shows strong and rapid variability, changing by a factor of four during the observation. The source displays modest spectral variability which is uncorrelated with flux.Comment: 5 pages incl. 6 figures, accepted for publication in MNRA

    Two-dimensional solitons at interfaces between binary superlattices and homogeneous lattices

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    We report on the experimental observation of two-dimensional surface solitons residing at the interface between a homogeneous square lattice and a superlattice that consists of alternating "deep" and "shallow" waveguides. By exciting single waveguides in the first row of the superlattice, we show that solitons centered on deep sites require much lower powers than their respective counterparts centered on shallow sites. Despite the fact that the average refractive index of the superlattice waveguides is equal to the refractive index of the homogeneous lattice, the interface results in clearly asymmetric output patterns.Comment: 16 pages, 5 figures, to appear in Physical Review

    Apollo 15 rake sample microbreccias and non-mare rocks: Bulk rock, mineral and glass electron microprobe analyses

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    Quantitative electron microprobe data of Apollo 15 nonmare rake samples are presented. Bulk analyses of lithic fragments in the nomare rocks (expressed in oxide weight-percent) and the corresponding CIPW molecular norms are given. The mineralogy of the rocks and lithic fragments are also given; structural formulae for complete analyses and molecular end-members for all mineral analyses are included. The mineral analyses include pyroxene, olivine, plagioclase, barian K-feldspar, spinel and ilmenite, cobaltian metallic nickel-iron as well as SiO2-K2O-rich residual glass. Electron micropobe analyses (oxide weight percent) of glasses in loose fines and microbreccia samples and their CIPW molecular norms are presented along with electron microprobe data on bulk, mineral, and matrix glass from chondrules

    Tables of Hyperonic Matter Equation of State for Core-Collapse Supernovae

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    We present sets of equation of state (EOS) of nuclear matter including hyperons using an SU_f(3) extended relativistic mean field (RMF) model with a wide coverage of density, temperature, and charge fraction for numerical simulations of core collapse supernovae. Coupling constants of Sigma and Xi hyperons with the sigma meson are determined to fit the hyperon potential depths in nuclear matter, U_Sigma(rho_0) ~ +30 MeV and U_Xi(rho_0) ~ -15 MeV, which are suggested from recent analyses of hyperon production reactions. At low densities, the EOS of uniform matter is connected with the EOS by Shen et al., in which formation of finite nuclei is included in the Thomas-Fermi approximation. In the present EOS, the maximum mass of neutron stars decreases from 2.17 M_sun (Ne mu) to 1.63 M_sun (NYe mu) when hyperons are included. In a spherical, adiabatic collapse of a 15MM_\odot star by the hydrodynamics without neutrino transfer, hyperon effects are found to be small, since the temperature and density do not reach the region of hyperon mixture, where the hyperon fraction is above 1 % (T > 40 MeV or rho_B > 0.4 fm^{-3}).Comment: 23 pages, 6 figures (Fig.3 and related comments on pion potential are corrected in v3.

    Oscillation effects on supernova neutrino rates and spectra and detection of the shock breakout in a liquid Argon TPC

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    A liquid Argon TPC (ICARUS-like) has the ability to detect clean neutrino bursts from type-II supernova collapses. In this paper, we consider for the first time the four possible detectable channels, namely, the elastic scattering on electrons from all neutrino species, νe\nu_e charged current absorption on ArAr with production of excited KK, νˉe\bar\nu_e charged current absorption on ArAr with production of excited ClCl and neutral current interactions on ArAr from all neutrino flavors. We compute the total rates and energy spectra of supernova neutrino events including the effects of the three--flavor neutrino oscillation with matter effects in the propagation in the supernova. Results show a dramatic dependence on the oscillation parameters and in the energy spectrum, especially for charged-current events. The shock breakout phase has also been investigated using recent simulations of the core collapse supernova. We stress the importance of the neutral current signal to decouple supernova from neutrino oscillation physics.Comment: 40 pages, 19 figures, version v2 accepted for publication in JCAP. accepted in JCA

    Trapping cold atoms using surface-grown carbon nanotubes

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    We present a feasibility study for loading cold atomic clouds into magnetic traps created by single-wall carbon nanotubes grown directly onto dielectric surfaces. We show that atoms may be captured for experimentally sustainable nanotube currents, generating trapped clouds whose densities and lifetimes are sufficient to enable detection by simple imaging methods. This opens the way for a novel type of conductor to be used in atomchips, enabling atom trapping at sub-micron distances, with implications for both fundamental studies and for technological applications

    Nucleon Spin Fluctuations and the Supernova Emission of Neutrinos and Axions

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    In the hot and dense medium of a supernova (SN) core, the nucleon spins fluctuate so fast that the axial-vector neutrino opacity and the axion emissivity are expected to be significantly modified. Axions with m_a\alt10^{-2}\,{\rm eV} are not excluded by SN~1987A. A substantial transfer of energy in neutrino-nucleon (νN\nu N) collisions is enabled which may alter the spectra of SN neutrinos relative to calculations where energy-conserving νN\nu N collisions had been assumed near the neutrinosphere.Comment: 8 pages. REVTeX. 2 postscript figures, can be included with epsf. Small modifications of the text, a new "Note Added", and three new references. To be published in Phys. Rev. Let
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